Dental chuck



y 1944- H. 1. HOBDAY ETAL 2,347,741

DENTAL cHUbK Filed Aug. 10, 1940 Patented May 2, 1944 DENTAL CHUCK Herbert Leslie Hobday and Norman George Brown, Melbourne, Victoria, Australia, assignors to said Hobday Application August 10, 1940, Serial No. 352,138

. In Australia August 8, 1939 8 Claims.

This invention relates to improvements in dental chucks and tools for use therewith in making dentures.

The operations of cutting, filing and smoothing dentures or cases, preparatory to the final polishing operation, must necessarily be performed with care and with a high degree of ac.- curacy to ensure correct comfortable fitting. The cutting and filing operations, now performed manually, are laborious and oftentimes lengthy while the smoothing operation, which is also performed manually with the use of sand-paper or like abradant, is both long and tedious.

Our invention has for its'principal object the provision of means whereby cutting, filing and smoothing operations in the making of dentures is performed mechanically, and, in consequence, an appreciable saving in time and labour will be effected while maintaining the required standard of accuracy in the work.

Another object is the provision of a universally flexible or resilient chuck for operatively connecting a cutting, filing or other work tool to the live spindle of an electric motor or dental lathe, or other power source. whereby the use of these tools will be more efficient and made more convenient to the operator. while the risk of damage being caused to the dentures or cases in the performance of the work will be minimized.

A further object is the provision of a chuck which can be used advantageously for the mechanical performance of the sandpapering or smoothing operation in making dentures, the said chuck having means for the detachable and resilient mounting of the abradant.

A still further and important object is to provide improved cutting and filing tools which are constructed so that they can be conveniently fitted onto a cushioning element of the chuck and have a flexible mounting on said chuck.

According to the invention, we provide a chuck. having at one end means facilitating its operative connection to the live spindle of an electric motor or dental lathe, and at its opposite end means whereby cutting or filing tools of improved construction or, alternatively, an abradant such as sandpaper can be fitted thereon so as to have a flexible resilient mounting for efficient and speedy operation when the chuck is being rotated at high speed. The cutting or filing tool, or the Reference is now made to the accompanying explanatory drawing wherein:

Fig. 1 is a side elevational view of a dental chuck from which theresilient attachments have been removed.

Figs. 2 and 3 are opposite end views of the chuck illustrated in Fig. 1.

Figs. 4, 5 and 6 are views illustrating, respectively, a retaining ring: a cushioning sleeve: and a flexible coupling member, all of which are made of rubber or like resilient material and are adapted to be fitted onto the chuck.

Fig. '7 is a plan view of the chuck whereon the resilient attachments are fitted.

Fig. 8 is an end elevation of the chuck seen in Fig. '7.

Figs. 9 and 10 are views illustrating the use of the chuck for smoothing dentures or cases by the use of an abradant such as sandpaper.

Fig. 11 is a view of the chuck having an improved cutting tool resiliently mounted thereon.

Fig. 12 shows in end elevation the improved cutting tool.

Fig. 18 is a longitudinal section of the cutting tool on the line and in the direction of the arrows I3l3 of Fig. 12.

Fig. 14 illustrates a modified construction of resilient dental chuck within the ambit of the invention having and improved filing tool mounted thereon.

Fig. 15 is a vertical section on the line and in the direction of the arrows Iii-l5 in Fig. 14.

The chuck body is preferably constructed of suitable metal. It comprises a cylindrical member l which has a circumferential groove 2 and is formed with a shank 3 of reduced diameter providing a shoulder 4. At the end of the shank 3 there is a longitudinal tapered extension 5 which is screw-threaded. Fitted to the shoulder 4 is a longitudinal pin 6 which lies parallel to the shank 3 and is suitably spaced therefrom.

A circumferential flange 1' is formed on the end of the chuck member I. Drilled axially in said chuck member is a round hole 8 which extends from its flanged end to adjacent to the shoulder l and tapers inwardly. The diameter of the axial hole 8 is such that it can be fitted tightly onto the end of the live spindle of an electric motor or a dental lathe. By tapping the flange I with a suitable tool, the required driving fit of the chuck onto said spindle can be readily effected.

The retaining ring 9 of rubber or like elastic material is removably seated in the circumferential groove 2 of the chuck, and a cushioning sleeve It], also of rubber, is adapted to be fitted tightly over the shank 3. This sleeve has a longitudinal slot H freely accommodating the pin 6 when it is fitted in position.

A flexible coupling member l2 which is formed of suitable resilient material, such as rubber, is of slightly tapering configuration-see Fig. 6, and it has a rounded end l3 and an axial bore l4 whereby it is adapted to be rigidly, but detachably, fitted onto the tapering screw-threaded member 5. When so fitted, the wall of said coupling member is expanded and lies in alignment with the cushioning sleeve Iii fitted on the shank 3.

When the chuck is to be used for smoothing a denture or case, a sheet of sandpaper or like abrasive material, indicated by I5, is inserted at one of its edges between the longitudinal pin 5 and the cushioning sleeve l-see Fig. 9. The sandpaper is rolled completely around the sleeve 10 and the flexible coupling member 12, encircling the pin 6. The elastic retaining ring 9 is thereupon rolled from its seating 2 over the sandpaper and co-operates with the pin 6 to securelyrretain the abradant in correct operative position-see Fig. 10. The abrasive sheet, after being rolled, is crimped about the rounded end l3 of the flexible coupling l2, and the chuck is rotated at high speed.

The operator, while holding the denture or case against the rotating cylinder of sandpaper, keeps moving it until the required smoothing operation has been completed. In this action, the denture or case is cushioned by the rubber sleeve l0, interposed between the sandpaper and the chuck body, and in consequence there is very little, if any, liability of the denture or case being jolted out of the operators hand. After completion of the sandpapering or smoothing operation, the elastic retaining ring 9 is rolled back to its first position to be seated in the circumferential groove 2 and permit the ready removal of the abradant [5.

When it is necessary to cut or file a denture or case, a cutting tool or a filing tool is selected for the purpose, a cutting tool having ridges--see Fig. 11-and a filing tool teethsee Fig. I l-on its external surface.

We provide improved cutting and filing tools for use with the improved dental chuck, the same being illustrated by Figs. 11 to 14.

An improved cutting or filing tool, designated by I6, is of hollow thimble-like construction with a smooth bore I1, and its internal diameter is such that the flexible coupling member 12 can be fitted therein with a driving fit and constitute a resilient core for the tool. A small orifice 11a is formed in the end of the wall of the hollow tool to permit escape of air when the flexible coupling member l2, after being detached from the chuck, is being forced into the bore of the tool to be retained firmly in position by frictional engagement with the inner surface of said tool. The inherent resilience of said coupling member and the tools smooth bore of large diameter enable required rigidity of joint being effected between the two parts such as will retain them against independent rotational movement under all normal circumstances. The flexible coupling member l2 having the tool 16 mounted thereon is now screwed onto the threaded extension of the shank 3 as is shown in Fig. 11.

While holding the denture or case against the external surface of the rotating tool IS, the operator keeps moving it until the desired results have been obtained. In this action, the tool is permitted to have angular movements relatively to the axis of the chuck, and the tool at all times is cushioned by the coupling member l2 constituting a core of resilient character, which will absorb jars to prevent displacement of the denture or case from the operators hand.

The modification, which is illustrated in Figs 14 and 15, consists of a closely wound helical spring I 8 one end of which is adapted to be fitted tightly upon the end of the live spindle I9 of an electric motor, dental lathe or other power source, while its opposite end is driven into the large smooth bore of the filing or cutting tool 16. When said tool, in the performance of its work, is displaced so as to be angular to the axis of the shaft IS, the power will still be transmitted through the spring, the torsional strength of which will cause the tool to bear with desired firmness against the denture or case being made.

What we do claim is:

1. A dental chuck comprising, a cylindrical member axially bored for operative connection to the live spindle of a power source, a shank, a cushioning sleeve on said shank, a longitudinal pin spaced from said shank, to fasten a sheet of abrading material and a resilient coupling member detachably fitted to the end of said shank and adapted for the interchangeable mounting thereon or" a cutting or filing tool or abrading medium.

2. A dental chuck comprising, a cylindrical member axially bored for operative connection to the live spindle of a power source, a. shank, a cushioning sleeve formed with a longitudinal slot fitted on said shanlna longitudinal pin spaced from said shank and accommodated by said slot, said pin being operative to fasten a sheet of abrading material, a tapered screw-threaded extension at the end of said shank, and a resilient coupling member fitted to said extension, and a, work tool or abrading medium mounted on said coupling member. 7

3. A dental chuck according to claim 2, wherein its cylindrical member is formed with a circumferential flange and a circumferential groove, and an elastic ring is movably seated in said groove, for the purposes described.

4. A dental chuck according to claim 2, wherein the resilient coupling member has a rounded end and is axially bored for engagement with the screw-threaded tapered extension of the shank.

5. A dental chuck comprising, a cylindrical member axially bored for operative connection to the live spindle of a power source, a shank, a resilient cushioning sleeve formed with a longitudinal slot fitted on said shank, a longitudinal pin spaced from said shank to fasten a sheet of abrading material, and elastic retaining means for holding said abrading material when rolled about said cushioning sleeve.

6. A dental chuck comprising, a cylindrical member axially bored for operative connection to the live spindle of a power source; a shank; a resilient cushioning sleeve, formed with a longitudinal slot, fitted on said shank; and a longitudinal pin, spaced from said shank and accommodated by said slot, operative to engage and fasten a sheet of abrading material.

7. A dental chuck comprising, a cylindrical member axially bored for operative connection to the live spindle of a power source; a shank; a threaded extension of said shank; a resilient coupling member having a rounded end and an axial bore adapted to engage said threaded extension; a resilient cushioning sleeve, formed With a longitudinal slot, fitted on said shank; and a longitudinal pin mounted on said cylindrical member, spaced from said shank and accommodated by said slot, operative to engage and fasten a sheet of abrading material Wrapped about said shank and said coupling member.

8. A dental chuck comprising the combination of a shank, having an end adapted to operatively engage the live spindle of a dental lathe and the like, and an end formed as a coupling member adapted to operatively and detachably support a Work-tool; a cushioning sleeve supported on said shank; and a tool mounted on said coupling member, said tool being operative to terminally support a cylinder of flexible abrasive material mounted on said cushioning sleeve.

HERBERT LESLIE HOBDAY. NORMAN G. BROWN. 

